But this data, obtained in a Freedom of Information request by BBC Radio 4's The World This Weekend, shows how much of that fall has been among younger officers.

Cleveland reported a 74% drop in young officers - the highest figure among the forces.

"The reason for the change in the age profile of our officers is pretty simple," said a spokesman for police and crime commissioner Barry Coppinger.

Analysis

By Martin RosenbaumFreedom of information specialist

Police numbers have been falling due to the financial squeeze on the public sector - that is a widely publicised fact. But what hasn't been made known until now are the details of how the drop has been concentrated among younger officers.

These figures are collected by police forces in England and Wales for reporting to the Home Office. But the Home Office doesn't include them in the police statistics that it routinely publishes. The BBC obtained them by a request under the Freedom of Information Act.

They reveal that the number of officers over 40 has stayed roughly unchanged from 2010 to 2012, while the number under 26 has plummeted by nearly half in this brief period.

It raises questions about how representative the police force is, especially given the issues about relations between the police and young people in some areas. And it also can't help with the concerns about the level of physical fitness among the police.

"It is because we have not recruited officers for the past three years - a direct consequence of the funding reductions imposed through the Comprehensive Spending Review.

"In the past we have tended to recruit people between 21 and 25, so the recruitment freeze will inevitably have reduced the share of officers at the lower age bracket.

"This trend is likely to continue until we are in a position to resume recruitment and that is dependent on the funding position."

Winston Roddick, police and crime commissioner for North Wales, said he hoped his first budget would help lead to a substantial rise in recruitment of young officers.

"The current economic downturn has undoubtedly affected the recruiting of new police officers," he said.

"However, during my campaign to be elected commissioner, I identified increasing the number of officers on the streets as one of my five priorities. I believe this will reduce crime and allay public concern for safety."

Olly Martins, the PCC for Bedfordshire, which saw a 58% fall, said the implications of this trend were very worrying.

"To secure policing by consent, and thereby be as effective as possible, forces need to look like the communities they serve.

"This is particularly true when it comes to the need to engage with younger people, who are disproportionately represented both as victims of crime and among its perpetrators."